Siloxane containing prepolymers and polyamide-imides prepared therefrom

ABSTRACT

SILOXANE CONTAINING DIAMINE PREPOLYMERS ARE PREPARED FROM A REACTION MIXTURE OF A POLYSILOXANE DIAMINE, TRIMELLITIC ANHYDRIDE AND AN ORGANIC DIAMINE. SUBSEQUENTLY, THE SILICONE CONTAINING DIAMINE PREPOLYMERS ARE REACTED WITH ORGANIC DIANHYDRIDES AND SUBJECTED TO A HEAT TREATMENT TO FORM POLYAMIDE-IMIDE PRODUCTS WHICH ARE USEFUL AS PROTECTIVE COATINGS HAVING HEAT RESISTANT AND CORONA RESISTANT PROPERTIES.

Patented Mar. 27, 1973 3,723,335 We have now found that a prepolymer can be formed SILOXANE CONTAINING PREPOLYMERS AND POLYAMIDE-IMIDES PREPARED THEREFROM at relatlvely low temperatures by the macho a John T. Hoback and Fred F. Holub, Schenectady, N.Y., siloxane containing diamine, trimellitic anhydride and an assignors to General Electric Company No Drawing. Filed Oct. 1971, Sen No. 185,905 organic d1am1ne. These prepolymers can then be reacted Int 03 11 0 cos 31 24 with dianhydrides to form polymers WhlCh are useful U.S. C]. 260-465 E 9 Claims for preparing films, coatings and adhesives with corona resistance which cure to novel polyamide-imidcs. The polymers when coated on fibers such as glass, boron,

f t t f l l d t quartz, and carbon fibers or fabric and various finely rom a reac lOIl ITllX ure 0 a po ysi oxane iamine, rrmenitic anhydride and an o g diamine. Subsequently divided materials'such as metals, carbon, quartz alumina the silicone containing diamine prepolyme rs are reacted and Other CeIamICS represent COated materlal Structures with organic dianhydrides and subg'iected tg ahheat treFli which have good adhesion to the polymeric matrix. ment to form polyamide-imide pro ucts w ic are use u I n accordance wt r as protective coatings having heat resistant and corona T p esent mventlon the Pre resistant properties polymer 1s a composition having recurring structural units of the general formula:

R.' R.' N HH fii l a an,

ABSTRACT OF THE DISCLOSURE Siloxane containing diamine prepolymers are prepared Recently considerable interest has been shown in polywherein R is a divalent hydrocarbon radical, R is a siloxane amides and polysilox ane amide imides useful for monovalent hydrocarbon radical, Q is a divalent organic insulation and protective purposes where resistance to radical which is the organic residue of the diamine, l is heat and corona are important requirements. Holub et al., 40 an integfir equa1 to at least 1, for example, f 1 to 50, in U.S. Pat. 3,598,785, dis s s the Preparation of P and m is an integer equal to at least 1, for instance, from siloxane amides from t e reaction of an Organic 1 to 50. Formula I has been generalized and is intended trimelliti anhy and a Polysiloxane Containing to include the structure in which the residue of the organic Dally Silicon bonded diamine or the residue of the siloxane containing diamine 0 may be attached to the residue of the trimellitic anhydride E by either amide or imide linkages. The prepolymer is groups, wherein R is a divalent hydrocarbon radical, and subsfiqufilltly feactfd Wlth a f y to form a Z is a halogen, hydroxyl or methoxy radical. Furtherpolymeric composition of recurring structural units of more, Holub et al. in U.S. Pat. 3,598,784 discloses the the formula:

preparation of polysiloxane amides and polysiloxane wherein R, R, Q, l and m are defined as hereinabove, amide imides from the reaction of an organic diamine, R is a tetravalent radical which is the residue of the a tetracarboxylic dianhydride and a polysiloxane conorganic dianhydride and n is an integer having a value taining terminal silicon-bonded of about 50 to or more.

The prepolymers of Formula I above can be prepared by effecting a reaction of a mixture of ingredients como prising a diamino siloxane of the general formula: -R&Z III. R Ill groups, wherein R and Z are defined as hereinabove. l1

a diamino compound of the formula:

IV. NH QNH and trimellitic anhydride having the formula:

wherein R, R, Q and l have the meanings given above. Among the diamino siloxanes of Formula III which may be used in the practice of the present invention includes compounds having the following formulas:

The diamines of Formula IV above are described in the prior art and are to a large extent commercially available materials. Typical of such diamines from which the prepolymer may be prepared are the following: m-phenylenediamine; p-phenylenediamine; 4,4'-diaminodiphenylpropane; 4,4-diaminodiphenylmethane; benzidine; 4,4'-diaminodiphenyl sulfide; 4,4'-diaminodiphenyl sulfone; 4,4-diaminodipheny1 ether; 1,5-diaminonaphthalene; 3,3-dimethylbenzidine; 3,3-dimethoxybenzidine; 2,4-bis(,8-amino-tbutyl)toluene; bis(p-fi-amino-t-butylphenyl)ether; bis (p-fi-methyl-o-aminophenyl) benzene; 1,3-diamino-4-isopropylbenzene; 1,2-bis(3-aminopr0poxy)ethane; m-xylylenediamine; p-xylylenediamine; bis(4-aminocyclohexyl)methane; decamethylenediamine; 3-methylheptamethylenediamine;

4 4,4-dimethylheptamethylenediamine; 2,11-dodecanediamine; 2,Z-dimethylpropylenediamine; octamethylenediamine; 3-methoxyhexamethylenediamine; 2,5-dimethylhexamethylenediamine; 2,5 -dimethylheptamethylenediamine; 3 -methylheptamethylenediamine; S-methylnonamethylenediamine; 1,4-cyclohexanediamine; 1,12-octadecanediamine; bis (3-aminopropy1) sulfide; N-methyl-bis (3-aminopropyl) amine; hexamethylenediamine; heptamethylenediamine; nonamethylenediamine;

wherein R" is a tetravalent radical, e.g., a radical derived from or containing an aromatic group containing at least 6 carbon atoms characterized by benzenoid nnsaturation, wherein each of the 4 carbonyl groups of the dianhydride are attached to a separate carbon atom in the tetravalent radical, the carbonyl groups being in pairs in which the groups in each pair are attached to adjacent carbon atoms of the R radical or to carbon atoms in the R radical at most one carbon atom removed, to provide a S-membered or 6-membered ring as follows:

Illustrations of dianhydrides suitable for use in the present invention (with their future designation in parentheses) include:

pyromellitic dianhydride (PMDA); 2,3,6,7-naphthalene tetracarboxylic dianhydride; 3,3',4,4'-diphenyl tetracarboxylic dianhydride; l,2,5,6-naphthalene tetracarboxylic dianhydride; 2,2,3,3'-diphenyl tetracarboxylic dianhydride; 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride; bis 3,4-dicarboxyphenyl) sulfone dianhydride; benzophenone tetracarboxylic acid dianhydride (BPDA) perylene-1,2,7,8-tetracarboxylic acid dianhydride; bis(3,4-dicarboxyphenyl)ether dianhydride; and bis(3,4-dicarboxyphenyl)methane dianhydride,

and aliphatic anhydrides such as cyclopentane tetracarboxylic dianhydride, cyclohexane tetracarboxylic dianhydride, butane tetracarboxylic dianhydride, etc.

In order that those skilled in the art may better understand how the present invention may be practiced, the following examples are given by way of illustration and not by way of limitation. All out through tests were conducted in the manner described in US. 2,936,296. The corona tests (calculated on an equivalent thickness basis) were made according to ASTM D-2275-64T which specified the electrodes. The test chamber used was at 25 C. and contained CaCl -2H O to maintain the relative humidity between 17-20%. A voltage of 1200 volts was applied at 3160 Hz. (cycles/sec.)

EXAMPLE I mellitic anhydride, 11.1 g. (0.1 M) 1,3-bis(6-aminobutyl)- To a reaction flask flushed with nitrogen were charged tetmmeihyl disiloxane and N'inethylpyrrolidone 201) (01 m.) pp, methy1ene dianiline 192 g (0.1 M) were mixed and reacted. After collecting the theoretical trimeuitic anhydride 27.6 g (01 M) 1 3 bis(a amino amount of Water 3.6 g., the reaction was cooled to room butyl)tetramethyl disiloxane and 20.6 g. of N-methylpyr- 5 temperature i 2 of N-Ieethylpyrwhdone a mlidone. The mixture was heated with Stirring to added. The amidelmlde siloxane diamine upon analysis 195 C. for 8 hours during which 3.6 g. of water (theoretiwas found to contain? C, 734%; H, N, 101%; Si, cal amount) was collected. The resulting composition may Calculated f C34H29.2N4O3.2S10.4: c, 734%; be represented as being composed of a siloxane diamine 5.25%; 2.01%.

and an organic diamine of recurring structural unit of 1 With vigorous stirring 32.2 g. of benzophenone tetrathe formula: carboxylic dianhydride was added slowly to obtain a 30% O H o (EH; (3113 Nut [@om@-] H N- (CH2)4-SiOSi(CHz)l- NH3 E (EH. H3

The solution was cooled at room temperature and 160 g. of N-methylpyrrolidone was added and 32.2 g. of solids resin solution. Films were cast on glass and alumibenzophenone tetracarboxylic dianhydride was added num and then cured at 120 C.15 minutes, 200 C.15 slowly with vigorous stirring. The polyamide-imide amic minutes, and 302 C.- 15 minutes. These films were hard, acid resin solids in N-methyl-pyrrolidone) was cast flexible and had good adhesion to glass and aluminum. as a film on glass and aluminum substrates. The films were cured at 120 C. for 15 minutes, 150 C. for 15 minutes, EXAMPLES III-X and 302 C. for 15 minutes. Typically the curing step in- 30 volves gradually heating the film at a temperature of In these'examples polya mide-imide products were pre- 100-300 C. to remove solvent and to convert the amic pared, cast and cured into films, in the same manner as acid to the imide. The finally heat-treated film described described in the preceding examples employing trimellitic above was a polyamide-imide composed of recurring anhydride, various organic diamines and various tetrastructural units which may be represented by the formula:

O G u These films were clear, flexible and had good adhesion to carboxylic acid dianhydrides for making the polymeric both glass and aluminum. composition. The following table shows the molar concen- I trations of the ingredients used to make these polyamide- EXAMPLE H imide products together with the properties of the cured Using the procedure as set forth in Example I, 31.6 fil d i d on an l i substrate g. (0.10 m.) p,p'-methy1ene diauiline, 19.2 g. (.1 M) tri- Example III IV V VI VII VIII IX X Siloxane containing diamine prepolymer:

MDA

MA Properties of cured films:

u thru C.) 400 400 345 400 400 390 275 400 Corona (hrs 200 1, 200 256 Flexibility Pass Pass Pass Pass Pass Pass Pass Pass Adhesion m 1 These examples contain a minor portion of maleic anhydride While all the other samples contain a dian y dn'de; however, this is considered equivalent since two parts oi maleic anhydride are substituted for each p rt of thedianhydn'de which are reacted with the diamines to produce polymers.

2 The abbreviations in table signify the following: MDA=Methy1ene dianiline; MPDA=m-Phenylene dianiline; SDA=1,3bis(6-aminobutyl) tetramethyl disiloxane; TMA=Trimellitie anhydride; BPDA=Benzophenone dianhydride; PMDA=Pyromellitie dianhydride; MA=Maleic anhydride.

3 The flexibility test was performed by casting film on aluminum sheet, removing film by dissolving aluminumsheet with acid, running finger nail crease on dried film; passing films did not crack.

4 The adhesion test was determined by casting a film on ordinary soda lime glass, attempting to remove film irorrpltate; good adhesion was indicated by fact that film could not be removed easily.

8 It will be appreciated that the invention is not limited wherein R is a divalent hydrocarbon radical, R is a to the specific details shown in the examples and illustramonovalent hydrocarbon radical, Q is a divalent hydrotions and that various modifications may be made within carbon radical selected from the group consisting of alkylthe ordinary skill in the art without departing from the cue containing from 2-20 carbon atoms, cycloalkylene, spirit and scope of the invention. 5 alkylcycloalkylene, xylylene, phenylene, lower alkylphenylene,

We claim: 1. A composition having recurrent structural units for wherein X is a member selected from the group having wherein R is a divalent hydrocarbon radical, R is a 1-8 carbon atoms consisting of bivalent aliphatic, cyclomonovalent hydrocarbon radical, Q is a divalent organic 25 aliphatic or araliphatic, -O, radical selected from the group consisting of alkylene containing from 2-20 carbon atoms, cycloalkylene, alkylcyclo- 0 O alkylene, xylylene, phenylene, lower alkylphenylene, ii, S, and

ee M; a e

selected from the group having 1-8 carbon atoms conr sisting of bivalent aliphatic, cycloaliph'atic 0r araliphatic, R" is a tetravalent radical containing an aromatic group -O, containing at least 6 carbon atoms characterized by benzenoid unsaturation, wherein each of the four carbonyl groups of the dianhydride are attached to separate carbon 40 atoms in the tetravalent radical, the carbonyl groups being in pairs in which the groups in each pair are atlis an integer equal to at least 1, and m is an integer equal tached to adjacent carbon atoms of the tetravalent radical,

to t lea t 1, l is an integer having a value of at least 1, and n is an 2. The composition of claim 1, wherein R is lower alkyl, integer having a value of at least 50.

R is lower alkyl, and Q is said divalent organic radical 45 6. The polymeric composition of claim 5, wherein R which is the residue of a diamine. is lower alkyl, R is lower alkyl, and Q is said divalent or- 3. The composition of claim 2, having the recurring ganic radical which is the residue of a diamine.

structural formula:

CH3 CH 0 C 5. A polymeric composition composed of recurring structural units of the general formula:

7. The polymeric composition of claim 6, wherein Q is a member selected from and mixtures thereof, R is butyl, R is methyl, and R" is a member selected from the group consisting of and References Cited UNITED STATES PATENTS 3,392,144 7/1968 Holub 26046.5 10 3,598,784 8/1971 Holub et al. 260-46.5 3,598,785 8/1971 Holub et al. 26O46.5

DONALD E. CZAJA, Primary Examiner 15 M. I. MARQUIS, Assistant Examiner U.S. Cl. X.R.

117-124 F, 125, 126 S, 135.1, 139.5 A, 160 R, 160 A, DIG. 11; 26030.2, 46.5 G, 47 CP, 78 TF, 824 R 

